Formation and Evolution of Liquid Pools Entrapped within Primary Particles of In Situ Mg2Si/AM60B Composite with Fine-Grains during Partial Remelting

The formation mechanism and evolution of liquid pools entrapped within solid grains have been investigated during partial remelting of in-situ Mg2Si/AM60B composite with fine-grains during partial remelting. The results indicate that the merging of dendrite arms during the initial stage of partial remelting is the main cause for the formation of the entrapped liquid pools. In view of phase transformations, the formation of the entrapped liquid pools is attributed to the reactions of α+β→L and α→L, essentially. The evolution of the liquid pools during latter heating can be divided into two stages: the agglomeration of each others and connection with intergranular liquid.